Recipe 10.4 Adding Drop-Down Menus to Coolbars

     

Recipe 10.4 Adding Drop-Down Menus to Coolbars

10.4.1 Problem

You want to add drop-down menus to coolbars.

10.4.2 Solution

Create your own menus, catch the coolbar events you want to handle, and display the menus using the Menu class's setLocation and setVisible methods .

This is the same way context menus are created in SWT.


10.4.3 Discussion

If you give a coolbar item the style SWT.DROP_DOWN , it'll display a chevron button , also called an arrow button , when the full item can't be displayed. Clicking that button can display a drop-down menu with all the buttons in the coolbar itemif you know what you're doing.

As an example, we'll add a drop-down menu to the coolbar developed in the previous recipe. To make that menu active, we'll catch arrow button clicks (event.detail == SWT.ARROW) in the coolbar with this code in the class CoolBarListener :

 class CoolBarListener extends SelectionAdapter {     public void widgetSelected(SelectionEvent event)     {  if (event.detail == SWT.ARROW)   {  .                   .                   .  }  } } 

The objective here is to display the button captions as menu items, so we start by getting a list of buttons from the toolbar that was clicked:

 class CoolBarListener extends SelectionAdapter {     public void widgetSelected(SelectionEvent event)     {         if (event.detail == SWT.ARROW)         {  ToolBar toolBar = (ToolBar) ((CoolItem)   event.widget).getControl( );   ToolItem[] buttons = toolBar.getItems( );  .                    .                    .         }     } } 

Next we create a menu with items corresponding to the button captions:

 class CoolBarListener extends SelectionAdapter {     public void widgetSelected(SelectionEvent event)     {         if (event.detail == SWT.ARROW)                 {             ToolBar toolBar = (ToolBar) ((CoolItem)                              event.widget).getControl( );             ToolItem[] buttons = toolBar.getItems( );  if (menu != null)   {   menu.dispose( );   }   menu = new Menu(coolBar);   for (int loopIndex = 0; loopIndex < buttons.length;   loopIndex++)   {   MenuItem menuItem = new MenuItem(menu, SWT.PUSH);   menuItem.setText(buttons[loopIndex].getText( ));   }  .                        .                        .         }     } } 

Finally, we determine where the coolbar was clicked using the SelectionEvent class's x and y members and display the menu at that location using the Menu class's setLocation and setVisible methods:

 class CoolBarListener extends SelectionAdapter {     public void widgetSelected(SelectionEvent event)     {         if (event.detail == SWT.ARROW)         {             ToolBar toolBar = (ToolBar) ((CoolItem)                              event.widget).getControl( );             ToolItem[] buttons = toolBar.getItems( );             if (menu != null)             {                 menu.dispose( );             }             menu = new Menu(coolBar);             for (int loopIndex = 0; loopIndex < buttons.length;                              loopIndex++)             {                 MenuItem menuItem = new MenuItem(menu, SWT.PUSH);                 menuItem.setText(buttons[loopIndex].getText( ));             }  Point menuPoint = coolBar.toDisplay(new Point(event.x  ,  event.y));   menu.setLocation(menuPoint.x, menuPoint.y);   menu.setVisible(true);  }     } } 

You can see this new listener class, CoolBarListener , in the final code for CoolBarApp in Example 10-2. Note also that we add objects of this class to the two coolbar items as listeners in the code.

Example 10-2. Using SWT coolbars
 package org.cookbook.ch10; import org.eclipse.swt.*; import org.eclipse.swt.events.*; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; import org.eclipse.swt.graphics.*; public class CoolBarClass {     static Display display;     static Shell shell;     static CoolBar coolBar;     static Menu menu = null;     public static void main(String[] args)     {         display = new Display( );         shell = new Shell(display);         shell.setLayout(new GridLayout( ));         shell.setText("CoolBar Example");         shell.setSize(600, 200);         coolBar = new CoolBar(shell, SWT.BORDER  SWT.FLAT);         coolBar.setLayoutData(new GridData(GridData.FILL_BOTH));                  ToolBar toolBar1 = new ToolBar(coolBar, SWT.FLAT);         for (int loopIndex = 0; loopIndex < 5; loopIndex++)         {             ToolItem toolItem = new ToolItem(toolBar1, SWT.PUSH);             toolItem.setText("Button " + loopIndex);         }         ToolBar toolBar2 = new ToolBar(coolBar, SWT.FLAT  SWT.WRAP);         for (int loopIndex = 5; loopIndex < 10; loopIndex++)         {             ToolItem toolItem = new ToolItem(toolBar2, SWT.PUSH);             toolItem.setText("Button " + loopIndex);         }         CoolItem coolItem1 = new CoolItem(coolBar, SWT.DROP_DOWN);         coolItem1.setControl(toolBar1);         CoolItem coolItem2 = new CoolItem(coolBar, SWT.DROP_DOWN);         coolItem2.setControl(toolBar2);         Point toolBar1Size = toolBar1.computeSize(SWT.DEFAULT, SWT.DEFAULT);         Point coolBar1Size = coolItem1.computeSize(toolBar1Size.x,               toolBar1Size.y);         coolItem1.setSize(coolBar1Size);         Point toolBar2Size = toolBar2.computeSize(SWT.DEFAULT, SWT.DEFAULT);         Point coolBar2Size = coolItem1.computeSize(toolBar2Size.x,               toolBar2Size.y);         coolItem2.setSize(coolBar2Size);  class CoolBarListener extends SelectionAdapter         {             public void widgetSelected(SelectionEvent event)             {                 if (event.detail == SWT.ARROW)                 {                     ToolBar toolBar = (ToolBar) ((CoolItem)                              event.widget).getControl( );                     ToolItem[] buttons = toolBar.getItems( );                     if (menu != null)                     {                         menu.dispose( );                     }                     menu = new Menu(coolBar);                     for (int loopIndex = 0; loopIndex < buttons.length;                              loopIndex++)                     {                         MenuItem menuItem = new MenuItem(menu, SWT.PUSH);                         menuItem.setText(buttons[loopIndex].getText( ));                     }                     Point menuPoint = coolBar.toDisplay(new Point(event.x,                              event.y));                     menu.setLocation(menuPoint.x, menuPoint.y);                     menu.setVisible(true);                 }             }         }         coolItem1.addSelectionListener(new CoolBarListener( ));         coolItem2.addSelectionListener(new CoolBarListener( ));  shell.open( );         while (!shell.isDisposed( ))         {             if (!display.readAndDispatch( ))                 display.sleep( );         }         display.dispose( );     } } 

The results appear in Figure 10-3; clicking the chevron button that appears when you resize the coolbar items to partially obscure the first item displays the drop-down menu you see in the figure. Not bad!

Figure 10-3. Adding a drop-down menu to a coolbar
figs/ecb_1003.gif

10.4.4 See Also

Recipe 10.2 on creating SWT coolbars; Recipe 10.3 on adding items to coolbars.



Eclipse Cookbook
Inside XML (Inside (New Riders))
ISBN: 596007108
EAN: 2147483647
Year: 2006
Pages: 232
Authors: Steve Holzner

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